There are various situations in which controlling door movement is important. For example, it is useful to lock doors to prevent them from being opened except for under authorized conditions. There are a variety of known door locking mechanisms. Conventional, mechanical locks typically require a key to manipulate the lock for purposes of opening the door. More recently, electronic locks have been utilized in a variety of situations to control whether a door is locked without requiring a mechanical key.
Elevator systems also require controlled door movement. Elevator car doors and hoistway doors move together when an elevator car is at a landing to permit passage between an elevator car and the lobby. Many arrangements for coupling elevator car doors and hoistway doors together are mechanical in nature. Mechanical door couplers suffer from the drawback of requiring specific alignments that tend to complicate the installation process. Additionally, the mechanical components tend to wear over time and require maintenance.
Other elevator door coupler arrangements have been proposed that include magnets in place of or in addition to mechanical coupling components. Examples are shown in U.S. Pat. Nos. 5,487,449 and 3,638,762. The use of magnets in an elevator door coupling arrangement may overcome some of the drawbacks associated with purely mechanical coupling arrangements.